test: Add testing instructions

Author: srware

TEST.md

@@ -0,0 +1,4 @@
+## Testing
+The layer can be checked for common issues using the following command
+
+    yocto-check-layer /path/to/meta-iot-cloud --dependency /path/to/meta-openembedded/meta-oe /path/to/meta-openembedded/meta-python /path/to/meta-openembedded/meta-networking --no-auto-dependency